Research On Heat Transfer Performance Of Cold Radiation Plate And Combined Module Based On Optimization Of Heat Exchange Tube Spacin

Compared with the traditional all-air air conditioning system,the radiant cooling air conditioning system has attracted much attention due to its great potential in comfort and energy saving,but the uneven surface temperature distribution and relatively low cooling capacity per unit area,and the risk of condensation on the radiant cooling end surfaces restrict its engineering application.In this paper,the average surface temperature and temperature non-uniformity coefficient(TNC)are used as the evaluation indexes of the heat transfer performance of cold radiant panels,a heat transfer model of cold radiant panel heat transfer system is established based on the heat transfer mechanism of cold radiant panels,an experimental platform for radiation cooling is built,cold radiant panels with variable heat pipe spacing are designed,and the optimized combination of cold radiant panels with variable heat pipe spacing is carried out to study the heat transfer performance of cold radiant panels with optimized heat pipe spacing,and its combined module heat transfer performance based on the optimized heat exchanger pipe spacing,and the main conclusions are as follows.Under the condition of equal spacing of heat transfer pipes,the smaller the pipe spacing is,the average surface temperature and the maximum surface temperature decrease.When the number of tube rows are 4,5,6 rows,the corresponding variable pipe spacing mode than the fixed tube spacing mode surface average temperature are reduced,up to 0.37 ℃,0.56 ℃,0.36 ℃;its corresponding variable pipe spacing mode than the fixed pipe spacing mode TNC value are reduced,the surface uniformity is better,up to 19.3%,23.5%,30.3%.Under the conditions of different combinations of water supply flow rate and supply and return water temperature difference changes,the new type of variable pipe spacing cold radiator panel series combination module(VPS)is better than the conventional cold radiator panel series combination module(EPS)in improving the overall surface temperature uniformity and reducing the overall average surface temperature,and its overall heat transfer performance is better.The seven VPS combinations with the highest decrease in overall TNC values were all VPS-5 with the highest decrease of 18.92%,16.16%,and 16.03% compared to EPS-1,EPS-2,and EPS-3 combinations,respectively.Although the combination of cold radiant panels in series with variable pipe spacing will lead to the increase of cost and pressure drop,the increase of cost and pressure drop for the whole radiant cooling system is very small,and the heat transfer performance is improved.